Make calling slime-setup unnecessary

For a while now, the party line has been that slime-contribs is the way
to select which contribs are to be loaded. However, there were two
common scenarios that didn't work properly:

  1. (require 'slime)
     (setq slime-contribs <something>)

  2. Installing SLIME via package.el, then setting slime-contribs.

In both cases, the problem was that, after loading SLIME, changing
slime-contribs has no effect since it was only being taken into account
at load-time. This commit makes it so that we now look at slime-contribs
each time a new SLIME connection is launched.

README.md

@@ -26,7 +26,7 @@ Quick setup instructions
      ```el
      ;; Set your lisp system and, optionally, some contribs
      (setq inferior-lisp-program "/opt/sbcl/bin/sbcl")
-     (slime-setup '(slime-fancy))
+     (setq slime-contribs '(slime-fancy))
      ```
 
   3. Use `M-x slime` to fire up and connect to an inferior Lisp. SLIME will
@@ -40,7 +40,7 @@ Contribs
 --------
 
 SLIME comes with additional contributed packages or "contribs".
-Contribs can be loaded with the `slime-setup` function.
+Contribs can be selected via the `slime-contribs` list.
 
 The most-often used contrib is `slime-fancy`, which primarily installs a
 popular set of other contributed packages. It includes a better REPL, and

slime.el

@@ -943,6 +943,7 @@ See `slime-lisp-implementations'")
 (defun slime (&optional command coding-system)
   "Start an inferior^_superior Lisp and connect to its Swank server."
   (interactive)
+  (slime-setup)
   (let ((inferior-lisp-program (or command inferior-lisp-program))
         (slime-net-coding-system (or coding-system slime-net-coding-system)))
     (slime-start* (cond ((and command (symbolp command))
@@ -1061,6 +1062,7 @@ DIRECTORY change to this directory before starting the process.
                        "Port: " (cl-first slime-connect-port-history)
                        nil nil '(slime-connect-port-history . 1)))
                      nil t))
+  (slime-setup)
   (when (and interactive-p
              slime-net-processes
              (y-or-n-p "Close old connections first? "))
@@ -7492,8 +7494,6 @@ The returned bounds are either nil or non-empty."
 (run-hooks 'slime-load-hook)
 (provide 'slime)
 
-(slime-setup)
-
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